The present invention relates to a new class of ampholytic fluorinated surface-active agents, characterized in that they contain in the same molecule an aliphatic perfluorinated radical, a quaternary ammonium group and an anionic sulphonic group chemically bonded to the quaternary ammonium group by a bivalent group, which are especially useful as fire extinguishing agents.
Numerous amphoteric fluorinated surfactants are known. For example, the following compound is described in U.S. Pat. Nos. 3,258,423 and 3,562,156: ##STR2##
French Pat. Nos. 2,088,699, 2,088,941 and 2,084,888 describe the products of the following formulas: ##STR3##
These amphylotic products have been used for numerous applications in very varied fields, but particularly in the field of fire extinguishing agents (cf. for example Nos. 2,185,668 and 2,308,674).
However, these ampholytic surfactants are all carboxylic ampholytes, i.e., products wherein the anionic group is the carboxyl anion CO.sub.2.sup.-. Other ampholytic fluorinated surfactants have been described. Thus, French Pat. No. 2,373,551 claims compounds wherein the anionic group is the phosphorus anion and French Pat. No. 2,122,918 claims products wherein the anion is the sulphonic group SO.sub.3.sup.-, such as, for example: ##STR4## The sulphobetaines corresponding to this latter publication are characterized in that the quaternary ammonium and sulphonic groups contained in their molecule are both in the end position and are regarded as non-linear sulphobetaines.